Embodiments relate to a light emitting device, a light emitting device package and a lighting system including the same.
Nitride semiconductors are attracting much attention for the fields of optical devices and high-power electronic devices because of their high thermal stability and wide band gap energy. In particular, blue light emitting devices (LEDs), green LEDs, and UV LEDs that use nitride semiconductors have been commercialized and are widely used.
Light emitting diodes are now being used as a light source for a display device, an indoor and outdoor lighting, and a headlamp for a vehicle. Specifically, many products with respect to a high power LED applicable to a backlight unit (BLU) of such a LED are being developed.
An edge-type BLU structure is used for a relative small sized LED BLU, and a vertical-type BLU structure is used for a relative large sized LED BLU.
However, in case of the vertical-type BLU structure used for a large-area LCD, since it is necessary that a space having a thickness of greater than a certain thickness is defined to realize color mixing and uniform light-emission, it is impossible to reduce the overall thickness of the LED BLU to a thickness of less than a certain thickness. That is, in case of a whit LED using a phosphor, the uniform light-emission should be necessarily required. Also, in case of using, e.g., RGB LEDs, the LED BLU should have a thickness of greater than a certain thickness to realize white color through mixing of RGB colors and uniform light-emission.
To overcome such limitations, the LED BLU may be reduced in thickness using an optics lens having a specific shape. In this case, the optics lens may be complicated in design, and a light emitting pattern should be carefully considered. Thus, there are limitations that the design and manufacturing processes may be difficult, and an additional cost may occur.
Also, although a radiation pattern and a lens structure for realizing a light emitting pattern in a lateral direction are proposed in a related art technique, it may be difficult to design the lens, as well as manufacturing costs may increase.